138 NOTES ON LIFE-SAVING APPLIANCES. 



I have recently tested a pin-type davit loaded with 2,500 pounds dead weight 

 equalling a total load of 5,000 pounds on the two davits, which is slightly more than 

 the load on the quadrant-type davits at the Kilpatrick test. No difficulty was 

 experienced in swinging this load from the extreme inboard to the extreme out- 

 board position in fifty seconds with two men. This davit was listed inboard 6 

 degrees corresponding with the Kilpatrick list. It can be seen in operation by any 

 one interested. 



Mr. Harold F. Norton, Member: — The paper just read has presented some 

 very interesting information concerning life-saving appliances and has discussed 

 various forms of boat davits, among others, one or two unsatisfactory forms of what 

 is termed in the paper the "fixed-pin" type of mechanically operated davit. I 

 should like to mention a satisfactory davit of this type, the sheath-screw davit 

 (Plate 66). 



These davits have already been fitted on eight or ten ships and by several of 

 the principal yards, the Newport News Shipbuilding and Dry Dock Company, 

 Maryland Steel Company, the New York Shipbuilding Company, and the Quintard 

 Iron Works. A number of sets are being manufactured by the latter company for 

 boats of the Fall River Line. These sets are particularly interesting in that they 

 are fitted with a winch for lowering and hoisting the boat. By the courtesy of the 

 Quintard Iron Works Company a plan of the arrangement is attached (Plate 67), and 

 it is certainly a neat and compact arrangement of mechanically operated boat davit 

 and winch. One of these davits is now set up at the Company's works, 742 East 

 12th Street. 



The fixed pin-type davit shown in Plate 60 of the paper has a pin which is 

 obviously too short and not properly supported in the fore-and-aft direction from 

 the deck, nor is the support carried far enough up the davit arm, but the sheath- 

 screw davit provides against all these objections by the long and substantial pin, 

 with brackets extending well up the davit arm, and properly arranged deck con- 

 nections. It is, of course, perfectly easy to design a pin connection entirely capable 

 of accepting all of the strees transmitted to it from the davit arm, or which the deck 

 connections are capable of accepting. 



Another point commented upon is the liability of the screw-operated davit to 

 injury of the screw by the fore-and-aft swing of the boat. In the sheath-screw 

 davit the boat can never strike the screw but only the pipe sheath, and then only 

 for a short part of the motion at the beginning when the boat is rising from the 

 chocks, and when both sheath and screw are in positions to be least affected. Also 

 the fore-and-aft swing of the boat is by no means so violent as might at first appear, 

 which will occur to each member of the Society when he thinks of the necessarily 

 slow longitudinal period of oscillation of a ship of any size, and then applies this to 

 a pendulum of the length of the davit falls with the boat suspended above the deck, 

 and acting within the comparatively limited space between the end of the boat and 

 the davit itself. The quadrant davit illustrated in the paper appears to have no 



